US12315739B2ActiveUtilityPatentIndex 46

Isotropic silicon nitride removal

Assignee: APPLIED MATERIALS INCPriority: Oct 11, 2022Filed: Oct 11, 2022Granted: May 27, 2025

Est. expiryOct 11, 2042(~16.3 yrs left)· nominal 20-yr term from priority

Inventors:KOROLIK MIKHAIL GEE PAUL E YONG WEI YING DOREEN KOH TUCK FOONG SUDIJONO JOHN KRAUS PHILIP A CHUA THAI CHENG

H10P 50/242H10P 14/6687H10P 14/6336H10P 50/267H10P 50/283H01J 37/32422H01J 37/32357H01J 37/32H01L 21/3065H01L 21/02274H01L 21/02219H01L 21/32136

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Abstract

Exemplary methods of etching a silicon-containing material may include flowing a first fluorine-containing precursor into a remote plasma region of a semiconductor processing chamber. The methods may include flowing a sulfur-containing precursor into the remote plasma region of the semiconductor processing chamber. The methods may include forming a plasma within the remote plasma region to generate plasma effluents of the first fluorine-containing precursor and the sulfur-containing precursor. The methods may include flowing the plasma effluents into a processing region of the semiconductor processing chamber. A substrate may be positioned within the processing region. The substrate may include a trench formed through stacked layers including alternating layers of silicon nitride and silicon oxide. The methods may include isotropically etching the layers of silicon nitride while substantially maintaining the silicon oxide.

Claims

exact text as granted — not AI-modified

The invention claimed is:

1. A method of etching a silicon-containing material, the method comprising:
flowing a first fluorine-containing precursor and an additive precursor into a remote plasma region of a semiconductor processing chamber, wherein the additive precursor comprises a halogen other than fluorine;
flowing a sulfur-containing precursor into the remote plasma region of the semiconductor processing chamber;
forming a plasma within the remote plasma region to generate plasma effluents of the first fluorine-containing precursor and the sulfur-containing precursor;
flowing the plasma effluents into a processing region of the semiconductor processing chamber, wherein a substrate is positioned within the processing region, and wherein the substrate comprises a trench formed through stacked layers including alternating layers of silicon nitride and silicon oxide; and
isotropically etching the layers of silicon nitride while substantially maintaining the silicon oxide.

2. The method of etching a silicon-containing material of claim 1 , further comprising:
flowing a second fluorine-containing precursor to the processing region of the semiconductor processing chamber, wherein the second fluorine-containing precursor bypasses the remote plasma region.

3. The method of etching a silicon-containing material of claim 1 , further comprising:
halting a flow of the first fluorine-containing precursor and the sulfur-containing precursor after a first period of time; and
purging the processing region with a purge precursor.

4. The method of etching a silicon-containing material of claim 1 , wherein the sulfur-containing precursor comprises hydrogen sulfide or carbon disulfide.

5. The method of treating a silicon-containing substrate of claim 1 , wherein an etching selectivity between silicon nitride and silicon oxide is greater than or about 20:1.

6. The method of etching a silicon-containing material of claim 1 , wherein the first fluorine-containing precursor comprises sulfur, phosphorus, arsenic, silicon, carbon, selenium, or tellurium.

7. The method of etching a silicon-containing material of claim 1 , wherein the method is performed at a chamber operating pressure of between about 10 mTorr and about 5 Torr.

8. The method of etching a silicon-containing material of claim 1 , wherein the method is performed at a chamber temperature of less than or about 20° C.

9. The method of etching a silicon-containing material of claim 1 , further comprising:
flowing argon, helium, or nitrogen with the first fluorine-containing precursor and the sulfur-containing precursor.

10. The method of etching a silicon-containing material of claim 9 , wherein a flow rate ratio of the argon, helium, or nitrogen to the first fluorine-containing precursor is less than or about 2:1.

11. The method of etching a silicon-containing material of claim 1 , further comprising:
flowing a hydrogen-containing precursor with the first fluorine-containing precursor.

12. The method of treating a silicon-containing substrate of claim 1 , further comprising:
forming a passivation layer over the silicon oxide.

13. The method of etching a silicon-containing material of claim 1 , wherein a flow rate ratio of the additive precursor relative to the first fluorine-containing precursor is maintained at greater than or about 1:2.

14. The method of etching a silicon-containing material of claim 13 , wherein the flow rate ratio of the additive precursor to the first fluorine-containing precursor is maintained at less than or about 10:1.

15. A method of etching a silicon-containing material, the method comprising:
flowing a first halogen-containing precursor into a remote plasma region of a semiconductor processing chamber, wherein the first halogen-containing precursor comprises fluorine;
forming a plasma within the remote plasma region to generate plasma effluents of the first halogen-containing precursor;
flowing the plasma effluents into a processing region of the semiconductor processing chamber, wherein a substrate is positioned within the processing region, and wherein the substrate comprises a trench formed through stacked layers including alternating layers of silicon nitride and silicon oxide;
flowing a second halogen-containing precursor directly to the processing region of the semiconductor processing chamber, wherein the second halogen-containing precursor comprises chlorine, bromine, or iodine;
laterally etching the layers of silicon nitride;
halting a flow of the first halogen-containing precursor after a first period of time; and
purging the processing region with a purge precursor.

16. The method of etching a silicon-containing material of claim 15 , further comprising:
flowing a sulfur-containing precursor into the remote plasma region of the semiconductor processing chamber.

17. The method of etching a silicon-containing material of claim 15 , further comprising:
repeating the method for at least 10 cycles.

18. The method of etching a silicon-containing material of claim 15 , wherein the first period of time is greater than or about 30 seconds.

19. The method of etching a silicon-containing material of claim 15 , further comprising:
flowing argon or nitrogen with the first halogen-containing precursor.

20. A method of etching a silicon-containing material, the method comprising:
flowing a first fluorine-containing precursor and an additive precursor into a remote plasma region of a semiconductor processing chamber, wherein the additive precursor comprises a halogen other than fluorine;
flowing a sulfur-containing precursor into the remote plasma region of the semiconductor processing chamber;
forming a plasma within the remote plasma region to generate plasma effluents of the first fluorine-containing precursor and the sulfur-containing precursor;
flowing the plasma effluents into a processing region of the semiconductor processing chamber, wherein a substrate is positioned within the processing region, and wherein the substrate defines a trench through stacked layers including alternating layers of silicon nitride and silicon oxide;
flowing a second fluorine-containing precursor to the processing region of the semiconductor processing chamber, wherein the second fluorine-containing precursor bypasses the remote plasma region; and
isotropically etching the layers of silicon nitride.

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